1. The Field of the Invention
The present invention relates to intravenous catheter insertion devices which employ a sharp needle to introduce and emplace an intravenous catheter into a body vessel of a patient. More particularly, the present invention relates to intravenous catheter insertion devices having protective needle transposal means for transposing a used needle into a safety receptacle and having self-contained coupling means for preventing separation of the catheter from the device until such time as the needle has been transposed into the safety receptacle.
2. The Relevant Technology
The introduction and emplacement of intravenous catheters into a body vessel of a patient by trained medical personnel is a common procedure utilizing fairly standardized apparatus and methods. Although the procedure for intravenous catheter insertion is fairly simple, medical practitioners must learn, develop, and maintain good technique which accomplishes the procedure quickly and comfortably for the patient as well as safely for both the patient and the practitioner. Intravenous catheter insertion devices typically employ a sharp needle to introduce and emplace an intravenous catheter into a body vessel of a patient. The needle is positioned within the catheter and the sharp needle end extends beyond the catheter such that the needle and catheter can be introduced nearly concomitantly into the body vessel immediately after the vessel has been pierced by the sharp needle end. It is usually desirable to retain the needle within the catheter to some extent to facilitate guiding and maneuvering of the catheter to a desired emplacement position within the body vessel. Often, the catheter is rotated into position around the needle and moved forward and backward along the needle during these maneuverings. Once the intravenous catheter is satisfactorily positioned within the vessel, the needle is typically withdrawn from inside the catheter leaving the catheter within the body vessel.
It will be appreciated that the needle used to introduce and emplace the catheter has contacted the patient's blood and other body fluids. It is well-known that an accidental needle stick with a used needle or any reuse of a used needle may result in transmission of harmful contaminants or infectious diseases including diseases such as AIDS or hepatitis. Because of this threat, any used needle should be carefully handled and discarded in a manner that minimizes this risk.
Because of the safety concerns related to needle use, numerous safety devices for handling needles, including retractable needles and extendable sheaths of various types, have been developed. For example, U.S. Pat. No. 4,160,450 issued on Jul. 10, 1979 to Doherty, disclosed a housing to hold the needle following use. The housing is formed as a liquid flow chamber connected to the catheter. A patent issued to Lasaitis et al. on Apr. 7, 1992, U.S. Pat. No. 5,102,394, disclosed a catheter assembly having a needle attached to a tab member which could be moved to retract the needle into a protective shield member. A similar device is taught in U.S. Pat. No. 5,176,650, issued to Haining on Jan. 5, 1993. The Haining device, however, also includes means for locking the needle in both the extended and the retracted positions.
U.S. Pat., No. 4,747,831, issued to Kulli on May 31, 1988, taught an intravenous catheter insertion device having a spring-loaded needle-carrying block that retracts into a handle when a manually-releasable latch is triggered. U.S. Pat. No. 4,973,316 issued to Dysarz on Nov. 27, 1990, disclosed a spring-loaded piston for retracting a needle into the barrel of a syringe when a trigger element is disengaged from the piston. Two subsequent patents issued to Dysarz, U.S. Pat. No. 5,125,414 issued Jun. 30, 1992 and U.S. Pat. No. 5,129,884 issued Jul. 14, 1992. Both patents disclosed a spring-loaded piston for retracting a needle which is activated by unthreading a latch for use in connection with, respectively, a blood-sampling device and an intravenous catheter insertion device.
Despite the above-described devices and numerous others known in the art, some problems remain. In particular, some of the safety features require cumbersome or two-handed manipulations to activate. Some of the devices do not ensure retention of the needle after activation of the safety feature. The safety feature of some devices can be easily disabled or "reloaded" such that the needle can be reused. Many of the devices can be used to introduce and emplace a catheter whether or not the safety feature is activated thereby making the safety feature optional rather than mandatory.
U.S. Pat. No. 5,092,853 issued Mar. 3, 1992 to Couvertier II and disclosed a spring-loaded retractable needle adapted to be held in the extended position by resiliently biased jaws. The jaws could be released to permit needle retraction either by plunger movement within a syringe barrel or by relative forward movement of a catheter fitted with means to squeeze the jaws. It can be seen, however, that the catheter insertion device of Couvertier II is not a separate and self-contained device for use with conventional catheters but, instead, requires a specially adapted catheter fitted with means to squeeze the jaws and prevent release of the needle. Moreover, this special catheter must be properly attached to prepare the device for use and the special catheter must thereafter remain in the properly attached position until such time as needle retraction is desired. Because only very slight relative forward movement of the catheter will release the jaws and cause needle retraction, it is possible to inadvertently move the catheter slightly and prematurely retract the needle. Such slight relative forward movement and triggering of needle retraction can occur during typical manipulations directed to maneuvering the catheter into a desired emplacement position following introduction of the catheter into the body vessel. If the inadvertent premature needle retraction occurs after the catheter has been introduced into a body vessel but before the catheter has been guided and maneuvered into the desired emplacement position within the body vessel, satisfactory emplacement of the catheter may be hindered or even prevented such that the catheter must be withdrawn and another catheter insertion device obtained and used. Such slight relative forward movement and triggering of needle retraction could also occur even before the catheter has been introduced into the body vessel. If this inadvertent premature needle retraction occurs before the catheter has been introduced into the body vessel, the device must be discarded and a second device obtained. Such inadvertent premature needle retraction causing failure of the device during an urgent medical situation could have serious detrimental consequences.
It would be an advantage to provide a self-contained safety intravenous catheter insertion device which requires transposal of the needle into a safety receptacle prior to separation of the catheter from the device to thereby prevent a user from omitting or circumventing activation of the protective needle transposal means and to inhibit needle misuse by preventing the needle from being separated from the catheter in usable condition. It would be a further advantage to provide such a device wherein the needle is substantially irreversibly retained within the safety receptacle to thereby prevent needle reuse and to permit the safety receptacle and the transposed needle to be safely handled and discarded. It would be an additional advantage to provide an intravenous catheter insertion device having automatic needle transposal means triggered by positioning of the catheter at a selected position relative to the needle wherein such relative position is selected to minimize the possibility of inadvertent premature transposal of the needle into the safety receptacle.